Carburetor



vNov. 2 1926.. 1,605,280

C. L. RAYFIELD GARBURETOR Filed Nov. 3, 1919 4 Sheets-Sheet l Nov. 2 1926. v I

c. L. RAYFIELD CfkRBURETOR Filed NOV. 5, 1919' 4 Sheets-Sheet 2 v V I UR Char/esLRayf/e/d I NoVQ'Z, 1926f I C- L. RAYFIELD CARBURETOR Filed Nov. 5, 1919 4 Sheets-Sheet 5 www 15v QIDEK Charles L. RayY/e/d Nov. 2 1926. 1,605,280

0. L. RAYFIELD CARBURETOR Filed Ndv. 5, 1919 4 Sheets-Sheet 4 Patented Nov. 2, 1926.

UNITED STATES CHARLES L. BAYFIELD, F QHICAGO, ILLINOIS, ASSIGNOB T0 BENEKE MANUFACTUR- ING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATIGN OF ILLDTOIS.

CARBUBETOR.

Application filed November 3, 1919. Serial No. 3825,3520.

This invention relates to a type of carburetors known as overflow carburetors, whereintthe float chamber is supplied with fuel from an auxiliary chamber which first fills with fuel and then overflows into the float chamber and, when the float within the float chamber rises to a predetermined level operates to cut off the inlet to the overflow chamber. The invention also comprehends an improved arrangement of. priming pas sages for starting motor to which the carburetor is attached, as well as a novel compensating means of supplying fuel from different sources into the carbureting chamber to properly carburete the air for various conditions of operation so that-a proper fuel mixture is supplied to the engine under all conditions of operation and yet with the carburetor so constructed as to minimize moving arts.

It is t erefore an object of this invention to provide a simple type of tube carburetor with a minimum .of moving parts and provided with fuel supply means operating according to conditions of operation of the engine to compensate for the difi'erent quantities of air drawn through the carburetor to supply a properly carbureted mixture to the engine for all conditions of operation thereof.

It is also an object of this invention to supply a side outlet carburetor having a plurality of fuel nozzles and with an overflow chamber supplying fuel to the float chamber with one of the fuel jets supplied 1 directly from the overflow chamber and another supplied both from the overflow and float chamber, and arranged with a system of air and fuel passages to properly compensate in the supply of fuel, for the difierent quantities of air drawn through the carburetor to supply a properlycarbureted mixture to the engine at all times.

' Other and further important objects of this invention will be apparent from the disclosures in the drawings and specification.

The invention (in a preferred form) is illustrated in the drawings and hereinafter more fully described.

Drawings.

Figure 1 is a top plan view'of acarbtiretor embodying the principles of my invention.

Figure 2 is a sectional detail with parts Figure 6 is a' side elevation of the carburetor with parts broken away and parts shown in section to illustrate the construction.

Figure 7 is a fragmentary enlarged section on the line 77 of Figure 5 showing a detail of the throttle shaft.

Description.

' The upper portion of the carburetor is cast as a unit comprising a casing denoted by the reference numeral 1 and is attached upon a,casin section 2 with an overflow chamber 3, ormed thereon and attached therebeneath is a third casing section aifording a float chamber 4 having a lateral extension 5 which extends beneath the overflow chamber 3. The chamber in the casing 1 which aflfords the mixing chamber and outlet of thecarburetor as shown clearly in Figure 4', is provided with an inserted-'Venturi tube 6 secured therein and an attaching flange 7 surrounds the outlet opening ofthe carburetor. Pivotally mounted within said casing 1 is a throttle valve 8, mountedupon a vertical operating shaft 9. At the opposite end ofthe casing section 1, an air inlet opening is provided, controlled by a choker valve 10 mounted on the vertical shaft 11. The shaft 11 a is extended downwardly through a boss 11 on the cover of the float chamber. is cored axially with the passage 11*, and has a transverse port 11. The transverse port 11 registers with a port 11 in the boss 11 when the choke valve is closed, to admit air into the float chamber.

The inlet of fuel for the carburetor is through a fitting 12 communicating into the upper end of the overflow chamber 3 by means of a passage 13 past an upwardly directed needle valve 14 having a stem 15 of triangular section. v A passaged seat memprovided with lateral apertures 26 at her 16 is threaded into an extension formed in the upper end of the'o'l' 'ertlow chamber 3 coinmunicating with the passage 13 to form :1 seat for the needle valve closure 14.

The stem 15 of the needle valve is slidably n'iounted in an uprightoverfiow tube or stundpipe 17 threaded into the floor of said overflow chamber 3 and secured on the stem 15 near the upper end thereof, is u hood or cup 18 having apertures 19 therein. Said hood is normally spaced above the upper end of the stendpipe 17 so that fuel entering past the needle valve M is spilled over said hood into the chamber 3 and as the level therein rises, the fuel flows upwardly heneeth the hood l8 and over the top of the stundpipe 17 for discharge therethrough into the float, chamber 4. The apertures 1%) prevent the forming of a sealwhich would cause siphoning of the fuel from the overflow chamber 3 into the Host chamber l. The lower end of the stem 15 rests upon a pivot "l lever 20, the free end of which is of yol're shape and rests upon the upper surface of o.

iloat, l. dispo-"ed in the float chamber 4:. A chamber 22 is "formed within the casing section 2 as shown in Figure 3 and threaded into the casing section is an epcrtured plug member 23. utlording a closure for the lower end of said chamber. Inserted tl'irough an aperture in the bottom of the float chamber 4 is a tube 24 threaded into said plug n1ernher 23 and having a nut 25 secured on the outer lower end thereof in scaling relation with the Wall of the flout chamber 4, and its upper end and apertures-27 at its lower end. A conical screen 28 held clumped mound the lower end of the tube enclosing the apertures 27. plug member 29, having; am upwardly projecting tubular.extension secured into the casino section 2 forming closure for the upper end the compartmerit or chamber 22 and inserted through said plug member and extending: upwardly and into the Venturi tube 6 in the casing section 1, is a tube 30 spaced from and extending downwardly in sealing relation through the plug member Said tube 30 is provided with fuel outlet apertures 31 near the upper end thereof and with apertures 53' communicating with the interior or": the tube 24 at the upper end of the float: chamber 4;

Said tube also extends downwardly into the tube 24 from which it is spaced, to a point slightly above the apertures 27. As shown clearly in Figure 3 the upper end of the member 2:) is swec ed inwardly into sealing relation with the tip of the tube uli 'ordingz an annular possum ljhcreurouud which comi'mmicntes into the chamber 22.

in air inlet pnssr ge provided tor the lost chamber '41 in on extension of ihe osi1 ect on 2 l5 shown in Figure 3 and is controlled by a, manually adjustable nee valve which is locked in. adjusted p tion by u. nut 35. Cored within the casing 2 is e passage 36 communicating" the chamber 22 shown in Figures leading beneath an outlet passage '1 valve sent member forming an outlet from the overflow chamber 8. Threaded into the upper end of the overflow chamber is e plug element 39 having a passage thercthrough and threaded to receive an adjust uble needle valve 40 to control the flow through said passage 37and :1 springimpelled bell detent ll is provided in said element 3.) tohcer ogeinst the needle valve l0 to hold the some in adjusted position. Engaged around the lower end of the element 39 and also around the pusssged seat member 38 is cylindrical screen 4-2 so that; iluid leaving no overflow chamber 3 by way oi the possage 37' and passage 36 must pass through.

said screen.

Said passage 36 terminates in a vertical rent passage 43 formed on one side of the overflow chamber 3 and adapted to be closed by any one of e number of apertured plu members which may he select.- ly in: sorted therein to give the desired :tion to inlet oi air ihereinto. Ceremonies? to the lower end of the overflow chamber is e.v passage 44') which leads through the s K cs ing section 2 to a point beneath the Von turi tuhe t3 and there communicates with a nozzle 4-6 which is engaged through the czising section 1 and projects upwrlrdly through Venturi tube as clearly shown in ure 5.

[is cleerl" shown in Figures end 6 the ll'iwer end 0} the throttle valve sin-xii 9 is drilled u'riel y to uii'ord a passage 4i? is drilled transversely with apertures and respectively. posse closed above the transverse aperture 50 by plug: 51 and similarly at the end of the shaft is closed by another plug field irottle' vel ve shaft 9 is also provided with 1" a, peripheral groove 53 through-which 'rhe aperture -18 communicates, and cored within the casing section 2 1n I'QglSlQl. with cue grooved and transverse aperture 48 is e.

priming passage conununicatinc' with an inclined priming passage 55 leading" into the outlet of the carburetor beyond the throttle valve 8 thereof. 'This passage 54 communicates with an enlarged passage 5L6 formed in the casing section 2 shown in dotted lines in Figure 4., and leads to and communicates with e vertical. iil'. formed in an extension on one side of: the casing section 1 as shown in Figure 8" lso coinmunicsting into the. lower end of passage 57 is an idling tubc or which. at its lower end connects W1 formed in a. 'ifil ll jfil em Ill? aeoaaso the float chamber and communicating into the interior of said chamber at its lower and. Rotatably mounted in the a right passage 57 .is a tubular rotatable closure element 60 having an aperture 61 near. its lower and adapted to register with a laterally directed air inlet passage 62 formed on the side of the casing section 1 and communicating into passage 57 through said tubular membar 80 when the same is in open position as- ,a-ohown in Figural Threaded into the tul a-rdly only sufiicient,

pillar plug as shown and extending downto partially restrict the opening 61 is a stem 63 with a head 64 and the adjustment thereof determines the quantity of fuel withdrawn by suction from the jet 58 and this depends upon the conditions of operation thereof. Attached upon the upper end of the tubular member l d is alcver 65 shown clearly in Figure 1. Said lever 65 is connected by a link 66-to another lever 67 which is secured upon the upper end. of the vertical shaft 11 for the butterfly choker valve 10.

The transverse aperture 49 through the throttle valve shaft 9 hereinbefore mentioned and clearly shown in Figures and 6 is adapted to register with an air port 49 shown directly in rear of said aperture in Figure 5 and provided in the casing section 2 to admit air into the upper portion of the canal or passage 47 within the throttle valve shaft 9 when the throttle is closed.

The passage 68 communicates downwardly and into the upper end of the float chamber 4 and when thetransverse aperture 50 registers with the passage 68 the interior of the float chamber 4 is opened to the atmos phere so that atmospheric pressure may be realized'upon the level therein.

As clearly shown in Figures 3 and 6, a drain cock 69 is provided in the lower'end of the float chamber 4 whereby the carburetor may be drained when desired. As shown in Figure 4 a screen 70 is provided in the inlet to the standpipe chamber 3 through the inlet fitting 12. As shown in Figures 1 and 4 a passage or canal 71 is cored in the side wall of the casing section 1 and communicatcs into, the outlet from the carburetor beyond the throttle valve and also with a fitting 72. This is provided for attachment of a vacuum fuel supply system and has no relation to the functioning of A throttle-lever 73 is at-' tached upon the upper end of the throttle valve shaft 9 and is adjustable thereon so as the carburetor.

to permit placing thereof in various positions for idling after attachment of the carburetor to an engine. Also attached upon the upper end of the aforesaid valve element 60 is an operating lever 74 which is adapted to be connected to any type or choker dash connection on a motor car so that by operation thereof the choker butterfly valve 10 may be opened and closed coinvalve .60.

Operation.

The fuel enters the carburetor through the fitting 12, passing through the screen 70 into the overflow chamber 3 and then rises therein until the level reaches a point of overflow into the upright standpipe 17 passing downwardly therethrough around the triangular valve stem into the float chamber 4. As the fuel fills up the float chamber 4 and the overflow chamber 3, the float 21 is elevated and finally upon reaching a predetermined level elevates the pivoted lever sufliciently to raise the stem 15 resting thereon to move the valve closure 14 into closed relation with the pass-aged seat member 16, through which the entering fuel flows. After the valve closure 14 has losed owing to the rise of level of the fuel in the float chamber 4, the level of the fuel in the overflow ch :nber 3, when the motor is at rest, is determined by the auxiliary nozzle 46, the discharge end of which is slightly below the upper end of the standpipe 19. The fuel will flow from the overassage to.

flow chamber 3 through the the nozzle 46 and outward y therefrom until the level in the overflow chamber is '40, and the fuel in said chamber 22 and the cident with rotational adjustment .of the annular chamber around the tube 30 rises to a level conforming to that in the overflow chamber 8 or at the same level as the discharge end of the nozzle 46. As clearly shown in Figure 5 this level is slightly below that of the apertures 31 in said tube 30. The normal level of the fuel within the tube 30 is that of the fuel in the float chamber 4 so that for the main nozzle of the cairburetor there are two levels, that within the annular space around the tube 30 corresponding to the level within the overflow chamber 3, and that within the tube 30 whichxis the game as that of the fuel in the float cham Assume first that the carburetor contains fuel and the motor to which the carburetor is attached is about to be started. The throttle valve 8 may be partially opened but the;

choker valve is entirely closed. Coincident;

62 and ass. result, the chamber '57 can only receive inlet thereto from the pipe 59 which communicates with the passage leading to the lower end of the float chamber t. The outlet from the chamber57 'consists of the passage 56 which leads to the passage 54:

' and this registers with the grooved periphcry 53 of the throttle valve shaft and also communicates through the transverse pussage 48 through said shaft with the continnation of the passage 53 and with the inclined passage 55 which enters the outlet end of'the carburetor beyond the throttle valve 8.

The result of this is a direct passage for raw fuel from the bottom of the float chamher into the outlet of the carburetor. A small amount of air is also admitted through the intern'iediate port 49 in the throttle valve shaft which communicates with the canal t7 and with an air inlet port in the carburetor casing, but the, relative areas of the ports for air and fuel arein favor of the fuel. so that a very rich mixture is supplied into the carburetor for the purpose of starting the motor. Immediately after the motor is started if advisable, the choker valve 10 is fully opened and as a consequence the air inlet to the float chamber is closed and the tubular valve element 60 is rotated into the posit-ion shown in Figure 6 so as to open the air inlet 62-into the chan'iber 57 thus breaking the suction effect to the float chamber through the pipe 59. The extent of opening. however," of the choker valve determines the extent of adjustment of the tubular valve element (it) and consequently determines the draft or suct on effect imposed upon the pipe comu-clion 59 leading to the fuel in the float chamber. Adjustment of the valve (it) to open position changes the relative areas of air to fuel passages, and enlarges the relative air areas to the fuel areas.

When the choker valve 10 is fully opened the valve element 60 is also adjusted into fully open position so as to provide a break in the suction or draft etlect in chamber 5"? which causes a flow of fuel from the float thamber. The extent of opening afforded by the valve element 60, however, is deter mined by theadjustment of the stem 63, by its head 64-, and this is the adjustment for idling: speeds of the engine. That is to say, the fuel withdrawn by suction through the tube 58 depends upon the restriction or suction effect permitted by inlet of air into the chamber 57 according to the adjustment of the stem 63 and the valve 60. A further restriction to the supply of fuel through the tube 58 is the regulated inlet for air into the float chamber-by the needle valve Set. The auxiliary nozzle 46 operates to supply fuel as long. as a supply of fuel existsin the overflow chamber 3. The overflow chamber is mitted to the float chamber.

,teoaeso maintained filled to the upper end tic; standpipo because of withd val of in i from the float chainher by the ieliiig tube which lowers the lost 32 and fuel the chamber 3, before additional fuel Thus "for in speeds of the engine fuel issupplied throi the small nozzle ill and the tube .58.

'lhefuel, of course, filling inent or well 22 sumnunding the cent of the nozzle rises in the annular k therearound to a point just below the 9,138? tures Ell, which, for intermediate speeds operation of the engine permit the fuel to be drawn from the annular passage into the tube and outv'ardly through the upper end thereof. This fuel. supply is normally under the same pressure as the float chamber for the reason that it is at the same level, as the fuel in the overflow chamber 3 and the overflow chamber 3 is in communication With the float chamber 4- through the standpipe 17. The adjustment of the needle valve air inlet 34- principally determines the restriction or pressure below atmospheric in the float chamber and consequently, the outlet oi fuel from both the overflow chamber and the float chamber.

As reference to Figure 3 will disclose the central tube 30 is provided with apertures 32 above the level. of fuel in the-float chant: ber thus permitting an inlet of air into said central tube for passage outwardly at the upper end of the tube when -fuel is being Withdrawn from the annular space surrounding the tube. Consequently the fuel supplied through the apertures at the upper end of the central tube is met by the stream of air passing through the central tube into the carburetinp; chamber and this supply of airpartially satisfies the demand due to depression and also obstructs by its volume the flow of fuel out oi the openings at the nozzle tip. Compensation is therefore provided both by interference at the top of the nozzle and resistance because of the sub atmospheric condition in the float chamber and is effective upon the fuel in the annular space surrounding the central tube.

For the intcrn'iediate speeds of operation of the engine, the adjustment of the car buretor is made by means of the needle valve air inlet 34, the adjustments for idling having been made. Thus fuel is supplied through the small nozzle 46, the tube 58 and the apertures 31 in the tip of the nozrlev feeding from the well 22. However, even at intermediate speeds the fuel is not supplied to the Well freely under atmospheric pressure even though the throttle valve may have been opened sufilciently to permit entrance of air into the float chamber bv way of the throttle valve shaft port 50. This is for the reason that the well 22 receives the fuel from the passage 36 which in turn tochamber If the vent passage 43 for the passage 36 were open, then the fuel would be at atmospheric pressure, but the vent passage is closed by a plug 44, having a small aperture which thereby restricts the pressure in the passage 43, 36 and well 22 when there is a tendency to withdraw fuel rapidly therefrom. I

The next consideration is the accelerative and high speed conditions'of operation of the engine. A sudden wide opening of the throttle will tend to empty the welli22 and likewise the nozzles 46 and 58 will increase their supply owing to the increased suction, and the opening of the float chamber to atmosphere through the port 50, in the throttle valve shaft to permit atmospheric effects to be realized therein. With the throttle wide open the central tube of themain nozzle supplies fuel directly from the float chamber and with a compensating effect.

As the throttle valve is opened for high speed or heavy load conditions of operation of the engine, fuel is supplied directly from the float chamber through the central tube 30 of the main nozzle. This is readily per- ,mittcd inasmucl: as the float chamber is open to atmospheric pressure through the passage (18 and port and the controlling effect of the air inlet needle valve 34 for the float chamber is negatived. The withdrawal of fuel through the nozzle tube 30 isrestricted for compensation by two factors, one the admission of air into the tube above'the level of fuel in the float chamber through the apertures 26 and 32 and the other, the size of the aperture 27 in the lower end of the tube 24, which admits fuel to said central tube 30. Thus for wide open throttle conditions of operation the fuel is supplied from the nozzle 46, the tube 58, the annular chamber or well around the main nozzle tube 30 and from the central nozzle tube 30 itself. The regulation in this carburetor for the fuel supplied is effected by a regulation of air admitted to the sources of fuel supply and this offers an ingenious, practical and efficient means offuel control.

-lhe size of the aperture 27, in the tube 24, however, is the main determining factor for supply of fuel to the central tube 20 of the main nozzle. for wide open throttle conditions of operation.

I am aware that various details of construction may be varied through a wide iaugc without departing from the principles of this invention and I therefore d0.not purpose limitin'g'the patent granted otherwise than necessitated by the prior art.

1. A carburetor of the class described comprising a float chamber, an overflow chamber feeding thereto, means in the overflow chamber controlled from the float chamber to control the inlet of fuel to the overflow chamber, a nozzle in communication with the float chamber, and with the said overflow chamber and having fuel at different levels therein, and an auxilia nozzle directly connected to the overflow c amber.

2. A. carburetor of the class described comprising a float chamber, an overflow chamber 'at a higher level feeding thereto, means in the overflow chamber controlling the inlet thereto and controlled from the float chamber, acompound nozzle communicating'with the float chamber and also with the overflow chamber permitting fuel to be supplied through the tip. of the nozzle from the overflow chamber at low speeds of an engine and both from said overflow chamber and float chamber at higher speeds and heavy loads on the engine, and an auxiliary nozzle havin the overflow c amber and operating to supply fuel during all'conditions of operation of the engine at which fuel is supplied from said compoundnozzle. v

3. A carburetor comprising a compound nozzle, a plurality of fuel sup ly chambers eachseparately supplying fuel to said nozzle whereby the fuel stands at different. levels in said nozzle and an auxiliary nozzle having direct communication with one of the supply chambers.

4. A carburetor of the class described comprising a compound compensating fuel nozzle, a plurality of sources of fuel supply each supplying fuel separately to said nozzle whereby the levels of fuel in said nozzle are at different heights therein, and an auxiliary nozzle in communication with one of said sources of fuel supply, said auxiliary nozzle adapted to discharge fuel from a level lower than oneof the levels in said compound nozzle.

5. A carburetor of the class described comprising fuel supply chambers at different levels, a compound nozzle in the carburetor, communication therewith from each of said fuel supply chambers, whereby the fuel supplied from the respective chambers is contained at different levels therein, and an auxiliary nozzle at a lower level than said compound nozzle and communicating with one of said fuel supply'chambers.

6.; In a carburetor of the class described comprising a plurality of fuel supply chambers, a plurality of nozzles in the carburetor,

direct communication with a plurality of fuel passages in one of the said nozzles. said passages in communication with said fuel supply chambers whereby fuel in said nozzle has different levels therein corresponding to the levels within the respective fuel supply chambers, passages providing communication between the respective levels of fuel within the nozzle at a point above the normal lercl of fuel therein whereby flow of fuel may take place from 5 one into the other and out of the nozzle when a suction draft takes place through the car-- buretor.

T. A carburetor of" the class described con'iprising' a plurality of fuel supply chann- 10 hers one above the other, an overflow pipe in the upper chaml'ier a compound compensating nozzle comprising a plurality of passages associated so that the fuel of all of said passages is delivered through the tip it of the nozzle and an. auxiliary nozzle in conunuuioatiou with one of the fuel supply chambers.

8. A. carburetor of the class described comprising a plurality of fuel supply chan1- 20 bers, one of said chambers adapted to supply fuel to the other thereof, a nozzle in the carburetor supplied simultaneously with fuel from both ofsaid chambers and an auxiliary (nozzle supplied with fuel from that chain- 25 her supplying fuel to the other chamber.

K). A carburetor coini arising a carburetor casing, a ,Venturi tube therein, a float chainbcr beneath the carburetor casing, a fuel nozzle projecting; into the Venturi tube and extending down :ardl into the float chamber a plurality of passages in said nozzle, an overflow fuel chamber communicating w th. he float chan'iber, con'ununicatioi'i between said overflow chamber and certain of the passages in said nozzle, and an auxiliary nozzle oro'ectin through. said Venturi tube sages is delivered through the tip of the nozzle and an auxiliary nozzle at a lower level than the upper end of said exertion pipe and in conurmnication with one of the fuel supply chambers.

11. A carburetor of the class described co-inprisii'ig a plurality of fuel supply chain hers, an overflow pipe in one of said chainbers adapted to supply fuel to the other thereof, a nozzle in the carburetor supplied. with fuel from both of said chaur 'iei's, and an auxiliary nozzle at a lower level than said overflow pipe supplied with fuel from that chamber supplying fuel to the other chamber.

12. carburetor of the class described comprising a plurality of fuel supply chain- JLl'S at different levels, a inulti-pasiaged fuel nozzle supplied with fuel independently from both of said chambers and an auxiliary fuel nozzle mounted adjacent thereto and oonm'iunicatiiig with one of said fuel supply cl'ianibers determining the level of fuel therein when the motor is stopped.

in testimony whereof I have hereunto sub-- scribed my name.

GHAELES L. RAYFIELD.

the overflow cl1a1n- 

